1. Field of Invention
The invention relates to a circuit structure in a display. More particularly, the invention relates to a shift register circuit configured in a display, which can generate a shading waveform.
2. Description of Related Art
In a conventional liquid crystal display, data lines and scan lines perpendicularly go across each others and form a pixel matrix. Scan lines, which are electrically coupled to gates of display transistors in the liquid crystal display, are configured for controlling switching states of display transistors, so as to determine whether to write image signals into the display transistors or not.
When liquid crystal units arranged in the pixel matrix are charged, a gate driving signal will be influenced by varied impedances, which vary corresponding to how many pixel units (on the same row/column) the gate driving signal has been passed through in sequence. Accordingly, the gate driving signal will be distorted gradually, which may cause an inconsistency of charging voltages of pixel units at different positions (on the same row/column). For example, the gate driving signal received at a near terminal located adjacent to a gate-driving circuit can be different from the gate driving signal received at a far terminal located away from the gate-driving circuit. The inconsistency of the gate driving signal may cause a flickering problem on the display panel. To solve the flicker problem, the gate driving signal is usually formed with a shading waveform (e.g., a chamfered waveform) as a conventional solution. For example, a gate-shading module, which is added to between a time sequence controller and a gate circuit, is configured for shading the gate driving signal (e.g., into the chamfered waveform), so as to reduce the influence of unequal impedance over pixel units, and maintain consistency of the gate driving signal to different liquid crystal units. In this case, the charging voltages on the different pixel units can be equalized to solve the flicker problem.
Currently, the function of generating a gate-shading waveform is mostly provided by a gate driver IC (or by configuring a gate-shading circuit element within the gate driver IC). Therefore, the circuit board of display reserves some space to implement the gate-shading circuit along with (or within) the gate driver IC.
However, in an advanced Gate on Array (GOA) process, there is no additional gate driving circuit implemented independently. However, the function of the gate-driving circuit is integrated on the display panel, so as to reduce an area occupied by the gate-driving circuit and realize a narrow bezel on the display panel. In this case, it is important to realize the gate-shading function on the gate-driving waveform of the display panel with a simple circuit structure.